Electric signal-transmitting means



J. McFELL. ELECTRIC SIGNAL TRANSMITTING MEANS.

APPLICATION FILED SEPT. 13, 1915.

Patented July 8, 1919.

3 SHEETSSHEET 1.

J. McFELL. ELECTRIC SIGNAL TRANSMITTING MEANS.

J. McFhLL.

ELECTRIC SIGNAL TRANSMITTING MEANS.

APPLICATION FILED SEPT. 13, 1915- I Patented July 8, 1919.

a sHLETs-sHEET 3.

J'UDSON MOFELL, OF CHICAGO, ILLI N'OIS.

ELECTRIC SIGNAL-TRANSMITTING MEANS.

Specification of Letters Patent.

Patented July 8, 1919.

. Application filed September 13, 1915. Serial No. 50,382.

To all whom it may concern I Be it known that I, J UDSON MCFELL, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have inventedcertain new and useful Improvements in Electric Signal-Transmitting Means, ofwhich the following is a specification.

My invention relates to electric signal transmitting means, and has for its general object to provide signaling means by whlch a code-signal may be transmitted telegraphically to a central station from the automatic transmitter or box at any one of a plurality of signal initiating stations, such auto- 1natically-transmitted signal indicating both the individuality of the user and the number of the particular station from which he is transmitting; and a further object of my invention is to provide such apparatus as will record the signals received at central in most convenient form.

Another object of the invention is so to construct and arrange the apparatus that the central-station authorities may cause a signal to be transmitted back to any selected user, individually, incidentally to his transmission of his individualsignal to the central station, no matter from What one of the signal-initiating stations said user may be effecting his signal-transmission; that is to say, by way of illustration, I make provision whereby it central wants user 23, central may set the central apparatus so that user 23, only, will be answered back when he turns in his signal, whether the user transmits from box 00, box 100 or any other box.

Other objects or" my invention are to provide an effective, eflicient, and simple systemic arrangement and suitable advantageous, rugged, easily-operated apparatus for attaining .the stated results; and generally and in detail to make provision for the economical and easy installation and maintenance of an efiiciently working system to the stated ends.

Many other and further objects of my in- "ention, more in detail, will become apparent to those skilled in the art from the fol lowing descriptiontaken in conjunction with the accompanying drawings in which Figures 1, 1 and 1 jointly constitute a diagrammatic illustration of a system em bodying my invention;

5 Fig. 2 illustrates a transmitter structure schematically shown in perspective; Fig. 2 shows a key therefor, and Fig. 2 details certain switch-control parts.

Fig. 3 illustrates a lock out circuit.

Fig 4 illustrates the first starting-operattion due to a preliminary-circuit-closure at the box.

Fig. 5 shows the second starting operation, due to the cirouit-break'terminating the preliminary impulse.

Fig. 6 show the signaling operation, as far as the register.

Fig. 7 shows the coordination of the reg ister and the answer-back selector.

Fig. 8 shows the answer back circuit.

While it will be apparent to those skilled in the art that many changes may be made in the construction and arrangement of apparatus, circuit-controlling parts, and circuits, within the spirit of my invention and within the scope of the appended claims, the inevitable complexity of such a system as that here in contemplation makes difficult and tedious the illustration and description of specific modifications, and I will, therefore, confine the description closely to full d1sclosure of one specific form of system,

. embodying the invention, that I prefer to employ; but without intent to limit my in: vention thereto in itsbroader aspects.

First generally to outline the plan of operation of the installation illustrated;

A A A representsignaling boxes or transmitters that constitute the signaling apparatus at a plurality of signal initiating stations. According to the particular central station mechanism herein shown, of these transmitters may conveniently be taken care of. And each transmitter will serve 100 users but, as will become apparent,

systems of larger or, smaller capacity may be made in accordance with my invention.

These transmitters are associated with a centrally-energized line equipment, shown as consisting of three wires 9, n, and Z, that I will respectively term, for convenient identification, the positive, negative and lockout wires. In a general way, two of these wires, p and n, are used in the signaling circuit; the third wire, Z, which also has connection to the negative battery terminal is used as a return for lock-out or non-interference purposes. v

Each transmitter is preferably'an automatic box of-the spring motor type, adapted to be wound by a key K. Each user has a different key, and, by the preferred construction. shown, the form of the key is the mechanical factor that will result in settin the transmitter to send a signal individua nal wheel a associated with a signaling switch a ,-and adapted, When' rotated, to

work the signalin switcha to transmit I notches .the turning'of the key, performed in winda circuit is closed), then closure of the switch first an individua key-set number-signal from the tens and units notches t and u and then a box-number signal, from notches t and u. For the box-number the signal Wheel notches'are permanently cut; for the individual number there are, preferably, ten provided in each digit group, but

ing the box, acts to set appropriatedisabling mechanism so that on y a, selected num-' ber of notches for the appropriate 'use'rs signal will be effective to operate the signal switch a If nine of the ten notches of each digit group are, thus rendered meflective the result will be the 'settin of signal 00 on the central register, an so, correspondingly, when box 69 is wound by key. 20, say, the signal switch will be operated to send groups of impulses numbering, successively 3, 1, 7, 10, or when user 55 signals from the same box, his key sets the mechanism to send 6, 6, 7, 10.

The running down of the box will transmit such four-digit-group signal over the line wires go, a to be recorded at the central station by a recorder that has on its record wheels numerals from 0 to 9.

The lock-out feature preferably provided, prevents signal clashes or interference, after the following fashion: The winding of the transmitter necessitates a key impelled rotation of a suitable part, as winding plate a that may be disabled from rotation by a disabling latch a controlled by a disabling magnet or lock-out-magnet a. The very first movement of this winding plate a closes the busy-test switch a that is included, with the magnet a in a circuit normally open at the central station when the system is' idle, closed at central when the lineis busy, such circuit including the third wire Z. If any other transmitter be operating (or, in other words, ifv the central-station control switch of the look-out a will energize lock-out magnet a, causing it to attract its latch on to oppose plate a send a preliminary impulse to central Sta tionrfor certain preparatory purposes to be described, (one of which is closure of the central station switch for the look-out circuit).

The subsequent rotation of the signal wheel a works the signal switch a as described to send the four-di it signal to 4 apparatus to indicate a certain individual number, the transmission of that number (and that only) will work the central station apparatus so asto make central closure of the ansWer-back-circuit, and consequently the answer-back buzzer a will fully operate to apprise the user that he is wanted at central.

At the central station I have shown two instrument sets B and C, the first being generically the signal recording apparatus and the latter being generically the answer back selective apparatus. I prefer that the recording apparatus be of the printin type and various orms may be used, but have shown a novel recorder having number wheels in accordance with the number of digits that may be transmitted as a signal from any box, and with these supplemented by horological indicating wheels, so that, on a suitable tape, the recorder may print on a transverse reading line such an indication as 20, 69, 10:15 showing that user 20 signals from box 69 at 10.15 oclock.

The recorder mechanism at central 'station is shown generally as comprising four signal-set number-wheels or segments 6, b,

72", and b corresponding with the tens and units orders of the individual or key-set signal and of the box-number signal, respectively and supplemented by the horological wheels I), each number wheel peripherally having numerals 0 to" 9.

In "the particular apparatus shown the preliminary impulse (from transmitter switch a) incidental to the winding of a transmitter operates certain circuit-changing. apparatus D that I may term the starting device, so as to close (as far as the central station is concerned) the lookout circuit above mentioned, and also so 'asto condition the recorder mechanism B, as a whole, for its functional operations.

When the true signal transmission from the box begins the line-impulses work a stepup device E in accordance with the digitgroups of impulses. This step-up turns the shaft on which the number wheels of the recorder are shown as loosely mounted. Each of said number-recordin wheels is shown as connectible with this shaft by clutch mechanism, and to control the throwin' in or out of the clutches, thereby to bring the different wheels successively under the control of the step-up, E, I provide a shifter mechanism F.

This shifter mechanism is electrorespon sive and is arranged to operate each time there is a dwell in the signaling sequence, that is to say, as long as regular impulses of a digit group are working the step up E,

shifter F remains inert, but when a dwell occurs and step up E becomes inert, then the shifter F is energized and operates.

As the result'of the preliminary opera-' tion of the starting device D this shifter mechanism connects the first recorder wheel I) with the shaft because at that time the step up E is inert and the first group of impulses transmitted from the signal-boxsteps. the said wheel b forward. Between the tens-digit group, thus recorded, and the units-digit group of signaling impulses a dwell occurs in the signaling operation; the shifter operates during this dwell; the first said recorder wheel is thereby disconnected from the recorder shaft and the secondrecorder wheel I) is clutched to the shaft; wherefore the second group of signal im-. pulses, working the step up device E, steps forward this second wheel I). And so on throughout the' series of four impulse groups.

During the time that this stepping of the recorder number wheels is taking place, the two number wheels of the selector 0 forming part ofthe answer-back apparatus are being stepped up in harmony with the individual signal, just as are the first two wheels of the recorder device.' These selector wheels carry movable contacts to sweep over a series of stationary contacts and such stationary contacts are connected with the plug board 0. (Only a few of the plug sockets on board 0 are represented, but of course there will be as man plug sockets as there are users to be served.) If the central operator wishes to communicate with acertain user, say user 22, the first time such user transmits his individual signal for record, the central operator inserts a metal- I lie connecting plug 0 in plug socket 22, and

when user 22 signals, the selector 0 is automatically stepped up so that its traveling contacts, coming'to rest on fixed contacts connected with plug socket 22, are connected together through such plug; This operation effects a closure, at the central station, of connections necessary for establishing the answer-back circuit, and as a'result 0 such closure, (and of other automatic operations the calling user. Consequently before the users box has run down, closure of the answerback switch a. at the users box starts the buzzer a in operation and the user is apprised of the fact that he is wanted at central.

Since my present invention relates primarily to telegraphic signaling, I have not complicated it by illustration of telephonic auxiliaries, but it will be understood by those skilled in the electric arts that the central station and the transmitting stations may be connected by telephone, and that the line wiring may be used as part of the telephone wiring, if desired.

In the range of operation thus far outlined, the central station mechanism acts mainly in response to operations initiated at the transmitter. As far as the transmitter is concerned, it may be built simply to make its single round of operations and desist in its initial condition. The central station apparatus, however, (when of the type hereinbefore suggested involving a settable recorder and a settable selector,) must have its mechanical parts and its switches restored to initial condition upon completion of a signal cycle and this restoration may be effected by return springs under the control of automatic releasing devices that are arranged in circuits local to the central station. In the specific instance herein shown I prefer that the releasing devices be of two kinds, namely, normal releasing devices that are thrown into operation when the central recorder has otherwise completed its cycle of functions and has printed the signal record; and, second, (as a refinement) a retarded emergency releaser G that will work to throw all parts back to normal if, for any reason, the central recording apparatus is worked part way through a cycle and then stops for a certain length of time. Explanatorily of this last-mentioned feature, it is quite possible, for instance, that a repair man working on the line, (or any other cause of intermittent connecting of the line wires) might cause such temporary circuit-closures as would partly work the recording apparatus after the fashion of a signal, and if matters were left in this condition the central recording apparatus would be out .of step. With the retarded releasing apparatus shown, however, the retarded releaser G would work under such conditions, after a certain length of time,

signal-transmitting functions have been performed,) the printing mechanism may be used as a means to set the releasing devices in operation, and the automatic restoration of mechanical parts of the recorder may 00- The line.

Two wires 1) and n, running from the multipled boxes to the central battery CB serve all of the signaling purposes. At each box the preliminary switch a, the signaling switch a, and the answer-back switch a are bridged across these wires. But of course the circuit through these two wires is only intermittently closed in the box-operation. Hence, for lock-out purposes, a third wire Z is employed in conjunction with wire 17, is made connectible with the battery as soon as any transmitter starts in operation so that there may be a constantly-potentiated circuit for the look-out devices during all of the time that any transmitter is operating.

The transmitter.

The --transmitter mechanism, that acts, first, to busy test the line; second, to send a preliminary impulse; third, to transmit a key-selected, individual users-number-signal followed by a predetermined box-number; and, fourth, to close'the answer-back connections, all in the course of its single round or cycle, of operations, may be variously constructed in detail. Indeed, theoretically, hand-operated switches such as telegraph keys might be so deftly manipulated as to close the circuits in proper sequence and at proper intervals in lieu of the various motor-actuated switches, but for practical work this hand-operation is not feasible. It-will be appreciated that speed and regularity 'of spacing in' impulse-transmission are very important to the proper operation of the system, so that some form of mechanical transmitter is a practical necessity, and obviously a mechanical structure that makes such provision that the mere insertion and turning of a key may condition the device for full performance of a whole sequence of functions is hi hly desirable, to speed up theoperation, o the system, to reheve the user of all needless work, and to avoid error. I

In the present drawing I have shown in Fig. 2 a diagrammatic representation of a transmitter suilicient to indicate the performance of all its important functions and to outline feasible mechanical construction.

Key K, when inserted, turned and withdrawn, winds the transmitter motor by'rotatingplate a that is part of the motor-- spring box and sets the transmitter in operation. The unwinding of the spring returns the plate a, and, through gearing a, drives the signal wheel a in rotation. In the wiring dlagrams, Figs. 1, 3, etc., mechanical relationships and directions of movement have been transposed in parts for simple illustrations. The plate a carries a knucklejointed stud a to close switches a and a on its winding movement but not on its return. The cam a for closing the answer-back switch may 'be directly on signal wheel a.

Key K has points k and k that set the box, its points is and k act upon, and ra-- dially extend or a of the two carried by a suitable frame a on wheel a and that correspond in peripheral succession with the notch-spacing of the signal wheel. As shown in Fig. 2, key for user 20 has projected the third in (marked a") of the tens order and the rst in (marked a) of the units order. Two wheel, following the groups of settable pins a in peripheral position, supplement said settable pins in o eration. The settable pins a do their wor as they passtherswitchcontrolling mechanism, that is appurtenant to the signal switch a; and during the further progress of the wheel the key-projected pins are pushed back to normal position by a fixed incline a. The signal switch a has project, appropriate pins roups. of ten pins that are I xed pins a on the a disabling cam a rotatable to four positions. Normally it leaves the switch a free to follow the signal wheel notches. Turned 90 it disables the switch by bracing it open;

at 180. it frees the switch again, and at 270 it disables the switch a second time. A

ratchet-cylinder a?. having four teeth moves a the cam a and is in turn moved against the tension of snap-s ring a" by the key selected pins a an fixed pins a". The keyprojected pins a and the fixed pins a move in a circle intersecting ratchet cylinder pin a operates the ratchet cylinder, turning ratchet-cylinder. to disabling position, and.

later the last fixed pin a removes the disability so that the switch ma answer freely" -to the permanent box-num er notches of wheel. a.

means D and lock-but The 'starting potentiatz'on.

The three wires 12, n and l (positive, negative and lock-out) to which all of the boxes are connected in multiple, extend to the central station where the wire 1/ is connected direct to the positive terminal, say, of a central battery CB while wire 11. is normally connected to the negative terminal of the'battery to wire 12. and the negative terminal of said battery through a switch '20 that stands normally open. The negative wire n leads into a normally closed switch 21 that has connection'by wire 22 through a starting .magnet 23 with the battery end n. of the negative line wire. Consequentl the system has no normally closed circu t, and the only circuit normall closable directly by any box is that whic includes the starting magnet 23. Thus the system, when idle, consumes no current.

When the transmitter preliminarily connects the wires through switch a, the circuit for the starter magnet 23 is established via CB p, a, n, 22, 23, n, CB The energized starting-magnet 23 attracts its armature 24 that controls a switching lever 25. When the armature is attracted a pin on the lever 25 escapes past the stop 26 on armature 21 and comes in contact withanother stop 27,

its motion being sufficient to close the negative line switch 20, that is used only in the lock-out circuit but without otherwise changing the condition of the switches associated with the lever 25. (See Fig. 1:.) Thus the lock-outcircuit is potentiated, but the signaling circuit is not. Should any other user now try to signal, he will be locked out as shown in Fi 3. p

The signaling circuit should not be closed until switch a opens, else the switch a.

would give a signal-impulse rather than only a-preliminary-torthe-signal1ng impulse.

When switch 11 opens and the magnet is deenergized, retraction of armature 24- enables switching lever 25 to pass on to ts final position. (See Fig. '5.) In so dolng it opens switch 21 (to cut out magnet 23) andcloses the switches 28 and 30. Switch 28 connects wire 29 with the negative wire 12.

to cut-the step-up devices into service and switch 30 connects wire 31 with the already closed switch 20, thereby to cut in the shifter devices. r

The general relation of step-up devices E and lock-out wire '11 is connectable and shifter devices F'is this: The step ii magnet is controllable by the signal switci of the transmitter, and its circuitextends, therefore, to the boxes; the shifter-magnet 1s controlled by a switch worked-by the step-up devices, and its circuit may be local to the central apparatus. The Shifter-magnet 1n the system shown, is energized only when the step-up devices rest lnert, and consequently the shifter magnet may be operated only during dwells in the operation of the step-up devices. Since the step-up devices are imtia-lly inert the shifter magnet Wlll be energized preliminarily before the step-up magnet begins to work at all.

The recorderm-cckaniam.

Because of its preferred construction in a form affording a plurality of number wheels, as heretofore suggested, the recorder mechanism is provided with two electric-magnets, one for stepping up the recorder shaft in response to line impulses and the other for shifting the operative connections between the respective wheels and the recorder shaft. Also this novel construction necessitates the use of special releasing devices.

It will be understood that while I have herein shown a form-wheel recorder that may conveniently print numbers from 00 to 999 as to both the box-numbers and individual numbers, the apparatus might be made with six wheels"- (for 1000-service, or with two wheels for service of as manystations and users as could be conveniently be enumerated on the periphery of a single wheel. Mere addition or subtraction of parts without reorganization in arrangement would accomplish this change of quantity-of service on the part of the recorder, and of course the transmitter could be made to send three-digit signals, or one-digit signals in place of the two-digit identifications of user and of transmitter herein expressly provided for.

When the starting apparatus functions as hereto-fore described, so that lever 25 is fully thrown to the left to close switch 30, (Fig. 5) a circuit is established for the shifting magnet 32 and the apparatus F via CB n, 20, 30, 31, shiftenmagnet 32, 33, yet-closed switch 34 (controlled by the step up magnet) wire 35, positive wire 39 p, CB Thus,'preliminarily, the shifter magnet 32 is energized and its armature 32 is thrown forward, acting through pawl 36 on a ratchet 37 fast on .a shifter shaft 38, advancing the ratchet one step, to be held by pawl 37 This shifter, in the particular construction shown, mechanically functions to con- 7 fast on the shaft 43 of the recorder.

clutch arc, of course, is normally spring disspacing of the ratchet 37. This preliminary forward step of theshaft conditions the first number wheel b to respond to the first 1mpulse group, as follows :-The rotatlve ad- Vance of the first arm 39 moves an arcuate clutch-element 40 that is. ivotally carried by the first number whee b, and pressed outwardly by spring 40', so that a tooth 41 of said are engages in a pinion 42, thaTth s engaged from the clutch pinion 42, and the wheel segment b is spring returnable to 1nitial position by a spring shown in dotted lines at 44. Of course, as long as the first arm 39 stands in the fore-mentioned position any rotation imparted to shaft 43 Wlll, through the clutch connection described, carry with said shaft the wheel I and the holding pawl 45 for the number wheel will restrain it in advanced position until release ,takes place. On the next step of the shifter shaft, however, the first arm 39 will pass. out of operative connection with the corresponding clutch are 40 while the second arm 39 will act similarly to connect the second wheel I) with the recorder shaft 43.

When the preliminary energization of the shifter magnet 32 has taken place, as aforesaid, connecting the first number wheel b of the recorder with the register shaft, the mechanism is ready for the reception of the signal. When the signal switch a is closed and opened by the notches of the transmitter wheel a, (Fig.- 7) it connects the llne wires p and n, making and breaking a circuit for the step up magnet 50 viathe path CB p, a n, 28, 29, a normally closed switch 51, wire 52, step-up magnet 5.0 and wire 53 to battery wire n and .battery CB Consequently the magnet 50 responds to the line impulses, its armature 50', through pawl 54, operating the-ratchet wheel 55 on recorder shaft 43.

The first impulse sent through magnet 50 opens the switch 34 that-is in circuit with the shifter magnet 32 and the shifter magnet is deenergized. Again to close the shiftermagnet circuit the armature 50 on the step-- up magnet must fall clear back to normal or inert position. This it does notdo as long as an uninterrupted sequence of impulses is being transmitted overlthe line, asis the case when the transmitter wheel is sending an impulse-group representing one digit of working,-in its retraction movement, a ainst a retard wheel 56, so thatit' may -vance rapidly but will retract slowly for the last or idle part of its return stroke. Consequently, it will be understood, the shifter magnet is idle-while the first group of signal impulses is being transmitted.

During the dwell that occurs between the transmission of successive impulse-groups the armature 50' for step-up magnet 50 has time fully .to retract, and consequently during the dwell after the first impulse-group has been transmitted switch 34 for the shifter-magnet is again closed, shifter magnet 32 is energized, and a step of the shifter occurs, disengaging the clutch forvthe first number wheel 6 and engaging the clutch of the second number wheel I). In like fashion the shifter advances after the second and the third impulse groups, and of course after the fourth impulse group has been transmitted there is a terminal dwell in signal transmission that results in the fifth forward progression of the shifter shaft.

Thus in general it will be seen that there will be a responsive movement of each re corder" wheel to the particular impulse Printing.

For circuit controlling functions the shifter shaft is provided with a cam member 60 shown as having three projections 61, 62 and 63. The projection 61 is so sha ed that on the fifth or final step aforesai it closes a normally open switch 64 that is in eluded with the printing magnet 65 in a circuit: CB p, 66, 64, 6 magnet 65, 68, n CB Consequently the printing magnet 65 is energized on the fifth step of the shifter, and throws forward its armature 65 so that its printing hammer 70 may strike a paper strip 71 against the number wheels that are suitably inked, thereby to make an impression of t e signal, together with the time, which is indicated by the selected number ofhorological wheels I). This printing operation completes the primary function of the recorder.

Releasing.

It will be realized that the printin operation takes place almost instantly a ter the final digit of the number signal has been transmitted, and after this printing-move- "ment, but before, the transmltter completes its operation there is I an interval during which the cam a of the transmitter is cloe- GB l he' 2 settable recorder i in the answer back switch a". ,It is during thls interval that the releasing operationatake place.

Of course, employed to record the signals, the releasing operation could be confined in the. cirwit-changing apparatus, 1 but with a recorder such asherein specifically described, provision must be made for the restoration of the mechanically set parts. With the herein shown, provision may best be made cal parts before the circuit controlling dparts are restored to normal position to con ition the line for further signaling, thus to avoid the possibility of a subsequent signal catch ing the register out of ticular installation shown,

battery CB and in part by asecond batfifth step of the'shi-ftenfthat conditions the printing. devices for operation, also results in the shifting of the long blade 51 of the shifter it has moved cam 62 to of switch 51 into connection with a back contact so closing the switch 71, cam 63 performing this operation. This switch 71, when closed, is latched by alatch 72 to be heldin closed position until the shifter is fully restored to initial position when a releasing link will lift the latch to releasing position. When the printing armature is thrown forward, also on the fifth shifter step aforesaid, it mechanically closes two switches 7 5 and 76 that are latched in closed position by appropriate latches 7 5 and 7 6'. Closure of switch establishes a circuit, for releasing magnet 77 via CB 19 78, magnet 77, 80, switch 7 5, 81, 68, n CB The magnet 7 thus energized attracts its armature, which is connected to the holding pawl 37 for the shifter ratchet 37, releasing said ratchet. ,Also a tail of the armature liftsthe live pawl 36 for said shifter ratchet-wheel out of engagement with the ratchet, the latch 83 locking the armature in its attracted position. Spring impelled restoration of the shifter shaft thereupon begins, but it is preferably retarded by a one-way retard escapement '84, at or before the fifth step ermit a switch 85 to open. At a proper tlme in the retarded return of the shifter wheel, cam 62 closes switch 85, that is arranged in series with a switch 76 as part of the releasing system. The idea 'of using the switches 85 and 76 in series is to hold off the second part of the releasing operation until the shifter gets suitably near. These two switches, thus concurrently closed, establish a releasing circuit for the magnet 87 that acts upon the switching lever 25 of the starting device D. Such circuit may be traced from GB, via 89, magnet 87, 9O, 91,

[vice D, and said switch were an ord nary tape recorderfor releasing the mechanistep. In the par-.

current for thereleasing operations is supplied in part by 4 for the power vter each printing 92,76, 93, 85, 94, GB. The magnet 87 draws over the switch lever 25 of the starting deattracted position by the armature 24 of the starting magnet 23, pending commencement of another signaling operation.

When the-shifter wheel 60, after its retarded return movement gets almost home an arm 100 of the shifter operates a lever system, graphically shown in general as 101, that throws out the pawls 45, for the recorder wheels, releases the latch 83 for the armature 37 of release magnet 77, and also throws out the latches 7 5 and 7 6' for the sw itches 7 5and 76 so that the latter, springing open,

break the circuits heretofore described for the two release magnets 77 and 87. Of course, the recorder wheels then rapidlyreturn to normal position under the'stress of their springs.

Time wheel movements.

As incident to the particular form of recorder shown the horological wheels 5 are caused regularly to advance by the operation of an electric clock 105 that is shown as controlling a step-up magnet 106, the armature 106' of which operates the ratchet wheel receiving one of said horoa circuit for these electrical 89, 108, 109,

logical wheels, parts being provided via CB Paper feed.

The paper feed that should takeplace afoperation may conveniently be made to be a concomitant of the action of the printer, but subsequent thereto in point of time, by making its operation coincident with that of the releasing devices that are controlled by the printer. In the specific illustration a paper feed magnet 115,'the armature 115 of which controls a step up pawl for a ratchet Wheel 116 for feeding the paper stri'p 71, is bridged'by wires 117 and 118 between the wires 92 and 109, so that when switches 76 and 85 are closed, simultaneously, as heretofore described, a circuit for said magnet is established Via CB 89; 108, 109, 118, magnet 115, 117, 7.6, 93, 85, 94, CB

Emergency release. I

the retarding device being thrown backto lever is latched inlarly operating box; jstartin'g magnet is energized and deenerits starting point, incidentally to the regular operation of the recorder, at intervals too short to permit it to perform Its releasing functions if the recorder 15 operatmg normally. A. failure of recorder-operation,

however, continuing for a certain period, gives the device time to function, and it .then operates to efi'ect a release of the recorder parts. This device, it will be understood, is a refinement that may be wholly omitted if desired.

For illustrating the construction and operation of such an emergency release, we,

will assume that two makes-and-breaks of the signalingycircuits between wires p and n have accidentally been made, as an incident, say, of some line-repairing work. The result of this accident upon the recorder may be the same as the result of a preliminary impulse and one signal-impulse of a reguthat is to say, the

gized and the starting switch-devices controlled by lever 25 are thereby worked; the shifter makes one step forward, and the second impulse steps forward the number wheel 6 one step. Then this accidental, partial operation ceases. The recorder is out of step and, except for the emergency-release device next box operation. I

The first advance of the shifter cam wheel causes cam 61 to close a switch 120 (which will be retained closed until the cam passes from under it incidentally to the fifth shifter-step). This switch closes a circuit for the operating magnet 121 of the emergency-releasing device G, via CB M, 123, 120, 124, magnet 121, 1-25, normally closed switch 126,127, 12 CB The armature 121 of the magnet 121 controls the switch 126, so that'the magnet makes and magnet 32 and will be.worked to throw out the holding pawl each time the shifter magnet is deenergized. Since, under the conditions now assumed, the shifter magnet is energized and will remain energized, and

the starting magnet has been workedand position pending" au-j will remain in shifted tomatic restoration,,the

holding paw l of the emergency device is free to do' its worl.

' leasing switches 75 and fore been described. These switches, when wires G, would so remain pending the out. The other lever 133 for throw- The continuous operation of the armature 65 121 for the emergency device, therefore,

- will advance the ratchet 130 through its full our in the normal operation of the system.

Under the assumed emergency conditions,

.however, the ratchet 130 is fully advanced and finally closes the two switches and 7 6 that are arranged in arallel with the re- 6 that have heretothrown closed, are latched in closed position by a latch 135 releasable by a link mechanism 136 that is operated upon full return of the ratchet 130. The switch 75" has connection by wires 68 and to the wires n and 79, just as have the corresponding wires 68 and 80 of the switch 75; while switch? 6 has connection 91 and 94 to the 91 and 94, so as to be in parallel with the twp switches 76 and that are in series in the regular releasing circuit. Consequently closure of the two switches 76 and 7 5 will energize both the releasing magnets 77 and 87, restoring the recorder parts to normal position and, (incidentally to the dee'nergization of magnet 32 after switch 30 is open) causing the holding pawl 131 for the emergency device to be thrown out, thereby freeing the ratchet 130 to return to normal position and, at the end of its return movement to throw out the latch 135 for the switches 75 and 76 through the tripping system 136.

- The answer back apparatus.

While I have shown the answer back apparatus at C as a separate apparatus, it involves in efi'ect only a set of electrical con- 'nections, for the electro-mechanical appliances employed in manipulatin these connections are substantially a duplicate of certain parts of the recorder mechanism shown, and if a recorder of the type herein illustrated is'employed, it .will be obv'iousthat the mechanisms of the selector and the recorder might be united. Both for schematic clearness' and practical reasons I prefer separaterecording and selectin' devices, however. Essentially the answer ack in the embodiment shown, consists of a. pair of movable contacts 150 and 153 that are stepped forward in precise accordance with the tens and units oups ofimpulses of the indiggdua 151m rsig'nals (just as are the wheels an H f of the reeorder),oand..that swee over'stationary contacts 151 and .154.whicli are connected-by 152 and 155111143113 ping respectively,to

grouping and units grou the plug sockets a of the plug-board 0 The movable contacts are connectible with the wires. 12 and ad the signaling circuit, preferably throu h a switch that is closed by the recorder mec anism subsequently to the eettin of the full signal. In the construction s own the switch 711 of the recorder that, as has been described, is closed by the fifth rogression of the shifter device, es-

tabli es connection between the wire 29 (that is in turn connected with negative .wir'e n,) and a wire 156 that leads to the tens movable contact 150, while units contact 153 has direct connection with a con- .socket the answer-back circuit is closed at central station, and, .accordingly, when the transmitter that is in use connects the answer back buzzer a with the signaling circuits by closure ofswitch a", an answer-back circuit is established via CB p, a", buzzer a, n, 28, 29, 71, 156, 150, 151, 152, the plugged socket 0 155, 154, 153, 71 CB A special socket 0* may be bridged across the wires 156, n so that, when it is plugged, no matter what user transmits the signal he will receive an answer-back call, since this connection short circuits the movable contacts 150 and 153. I

Since the step-up operations of the contacts 150 and 153 are intended exactly to correspond with the advances of signal wheels 5 and b that set the users individual signal on the recorder, the apparatus for effecting such advance of the selector contacts (if a separate selector be used) may be in substance a replica of the corresponding apparatus of the recorder, and the operations of the step-up magnet and the shifter magnet for the selector, as well as the release magnet, maay be made to take place synchronously with corresponding operations of the recorder parts.

As amatter of convenience I use a separate battery GB for energizing the step-up and shifter magnets of the selector and control the magnet circuits by switches associated with the correspondingly-functioned recorder parts. I 1

Specifically the step-up wheels a and 0 are clutchaible to the selector shaft by shifter mechanism, opera-ted by magnet 32 precisely as is the recorder-shifter heretofore described; and the step up mechanism for the" selector ratchet-wheel is controlled by a step up magnet 50. The magnet 50 has its circuit controlled by a switch 170 that is closed'every time step up 'magnet 50 of the recorder throws its armature forward, while the shifter ma trolled by a switch 171 that is closed every time theiarmature 32 of the recorder is thrown forward. The circuit for magnet 50 may be traced: CB 173, 174, 50, 175, 170, 176, CB The circuit for the shifter magnet runs CB 173, 177, 32, 178, 171, 176, GB.

The release magnet 87 for the selector parallels one of the recorderreleasing magnets, preferably the magnet 87 and to this end has its wires 180 and "181 connected respectively to wires 89 and 91 in direct parallel with recorder magnet 87, so as to respond to the samereleasing influences. In a this way it is assured that the selector will remain set until the shifter of the recorder has substan' "ally completed its return movements to normal position, and as heretofoie suggested, it. is during this time that the answer-back buzzer at the users station may operate. Y

I prefer that, even when the plug is not inserted to answer back the user who is signaling, the answer back circuit be employed to give him a distinctive notification of the fact that his signal has been received, so showing that the apparatus is in working order. To this end I provide in the selector C a switch 1'85 having its wires 186 and 187 bridged directly across the answer back wires of and 156', and arrange a lug on a cam wheel 187 of the shifter-mechanism of the answer back selector so that it will. momentarily close the switch 185 just before completing the fifth step of the shifter. At the time when this momentary circuit closure takes place the answer back circuit will haveibeen otherwise completed by the recorder and by the cam a at the transmitter, and consequently a very short operation of the answer back buzzer occurs. An answer back is readily distinguishable from this test signal, as the true answer is a relatively long ring.

As far as I am aware, this invention is the first to embody asystem wherein any user may key-set any one of a plurality of settable electro-m'echanical transmitters to send his individual code-signal and may, at whatever transmitter he is operating, receive an answering signal that is selectively set by the central operator to answer his individual code-signal only.

et 32 has'its circuit con- It will be understood that in its breads aspects my invention is not limited to the particular devices and specific circuit ar,

rangements herein. employed for full disclosure for many variations in specific 'embodiment may be made without d e arture from the spirit of my invention, wit 1n the scope of the appended claims. 0

Having described my invention, what I claim is:

1. The combination of a plurality of telegraphic signal-transmitters each havmg an electro-responsive lock-out mechanism and signal-impulse transmitting means, a ce ntral station signal-responsive device, a s 1gnaling circuit for said impulse-transmittm means and signal-responsive device, a loc out circuit for the lock out mechanism, and means operable prior to the slgnal responsive device for potentiating the lock out circuit for all other transmitters during the operation of any transmitter.

2. The combination of a plurality of telegraphic signal-transmitters each havlng an electro-responsi-ve lock-out mechanism and signal-impulse transmitting means, a central station signal-responsive device, a s1gnal1ng circuit for said impulse-transmitting means and signal-responsive device, a lock out circuit for the lock out mechanism, means operable independently of said signal responsive device for potentiating the lock out circuit for all other transmitters at the commencement of signal-circuit-closing operation of any transmitter and means for automatically releasing said potentiating means after conclusion of the signaling-operation of said transmitter.

3. The combination of a plurality of telegraphic signal-transmitters each having an electro-responsive lock-out mechanism and a signal-wheel and switch, a central station signal-responsive mechanism, a signaling circuit for the signal switches of the transmitters and the signal-responsive device, a lock-out circuit for the lock-outmechanism, means at the central station responsive to the signal-circuit-closin operation of any transmitter for potentlating the look-out circuit for the other transmitters, and means associated with each transmitter for closing the connection of the lock-out mechanism of that transmitter with said lockout circuit preliminarily to its signaling transmitting operation.

4. The combination of a plurality of telegraphic signal-transmitters each having an electro-responsive lock-out mechanism and a signal-wheel and switch, a central station signal-responsive mechanism, a signaling circuit for the signal switches of the transmitters and the signal-res nsive device, a lock-out circuit for the 100 -out mechanism, means at the central station responsive to the signal-circuit-closing operation of any transmitter for potentiati ng the lock-out circuit for the other transmitters, means associated with each transmitter for actuating said lock-out potentiating means for other transmitters preliminarily to the signaling operation of the transmitter, and means associated with each transmitter for closing the connection of the lock-out mechanism of that transmitter with said lock out circuit preliminarily to its signaling transmitting operation.

5. The combination of a plurality of motor-operated, manually-wound signaltransmitters, each having an electro-responsive lock-out mechanism for preventin motor-winding when energized and one liELVIIIIg signal-impulse transmitting means, a slgna responsive device at a central station, a signaling clrcuit for said impulse transmitters and signal-responsive device, a lock-out circuit for the look-out mechanism, and means operable preliminarily to the signal responsive device for effecting potentiation of the lock out circuit during the operation of any transmitter.

he combination of a plurality of motor-drlven, manually-wound signal-transmitters, each having an electro-responsive lockout mechanism for preventing motor Winding when energized, a switch for said lockout mechanism closable at the transmitter preliminarily to winding of the transmitter, and a signal-wheel and switch; a central stat1 on s1gnal-resp0nsive device; a signaling c rcuit for the si nal-switches and responslve devices, a 100 out circuit for the lock out mechanisms of the several transmitters, and central station electro-responsive means for potentiating the look-out circuits incidentally to the operation of any transmitter and subsequently to its own closure ofr the switch for its lock-out mechanism.

7. The combination of a plurality of telegraphlc signal transmitters, each having an electroresponsive lock-out mechanism and a signal-wheel and switch, a central station signal-responsive device, signal circuit wires for connecting the signal responsive device and signaling switch, a starting magnet normally operatively connected with said wires forresponse to the first operation of any transmitter, a lock-out circuit for the lock out mechanisms of the several transmitters normally open at the central station, and means controlled by the starting magnet for closing said circuit at the central station thereby to potentiate for operation the lockout mechanisms of all the transmitters except-the acting one.

8. In a system of the character described, a line, at a plurality of signal-sending stations, signal initiating means and answer back means, and at a receiving station signal receiving means and settable means coacting with the signal receiving means to condition for means at the sending station when thesignal transmitted accords with that for which the settahle means is set.

v9. In a system of the character described,

l l l I A a l a i 7' a 1me,\ variable-signal initiatmg means at onestation, answer back means associated therewith, signal receiving means at another station difierently responsive to the various signals and locally-controlled settable means at the last said station coacting with the signal-receiving means to condition the answer back for operation when the signal rece ving means responds to the signal for wlnch the settable means is set.

10. In a system of the character descr bed, a line, a plurality of transmitters associated therewith, each adapted to transmit its permanent number signal and a variable users signal, an answer-back signal device associated with each transmitter, and cooperating equipment comprising a settable dev ce and a signal responsive device 1o1ntly 1nstrumental in conditioning for operatlon the answer back of the sending station in response to a users signal in accord with the setting of said settable device.

11. In a system of the character described, the combination of a line, a plurality of im pulse-occasioning transmitters at respective sending stations, an electro-responsive answer-back signal means at each such station and, at a central station, a transmitteractuated circuit-controlling selector and means selectively settable b the central operator cooperating with t e selector to establish a circuit for potentiating the answer-back means only when the transmitter-occasioned operation of the selector corresponds with the setting of said settable means.

12. In a system of thecharacter described,

' the combination of a line, a plurality of impulse-occasioning transmitters at respective sending stations, each comprising a yar ablesignal, selectively-settable impulse mltiator, an electro-responsive answer-back signal means at each such station and, at a central station, a transmitter-actuated circuit-controlling selector and means selectively settable by the central operator cooperating with the selector to establish a circuit for potentiating the answer-back means only when the selectively set transmitter-occasioned operation f the selector corresponds with the setting of said settable means.

13. In a system of the character described, the combination of a line, a plurality of impulse-occasioning transmitters at respective sending stations, each comprising a keywound motor, and a key-set variable-signal impulse-initiator driven by the motor, an electro-responsive answer-back signal means at each such station and, at a central station, a transmitter-actuated circuit-controlling selector and means selectively settable by the central operator cooperating with the selector to establish a circuit for potentiating the answer back means only when the selectively-set transmitter-occasioned peration of the selector corresponds with the setting of said settable means.

14. In a systemof the character described the combination of a line; a plurality oi sending-station equipments each comprlsing a plural-digit signal transmitter and an electrically operated answer back signalmeans; and a central station equipment comprising circuit-controlling-means manually settable to accord with the plural-digit signal and a signal-responsive circuit-controlling selector having p'arts respectively movable in response to impulse groups of the signal-digits, said selector coacting with the manually-settable-means to potentiate the answer-back means of a calling station when the signal transmitted from said station. corresponds with that for which the centralstation means is manually set.

15. In a system of the character described, the combination of a line; a plurality of sending-station equipments each comprising a plural-digit signal-transmitter adapted to transmit a selectively-set signal individual to the user and an electrically-operated answer-back signal-means; and a central station equipment comprising circuit-controlling-means manually settable to accord with the plural-digit signal and a signal-responsive circuit-controlling selector having parts respectively movable in response to impulse groups of the signal-digits, said selector coacting with the manually-settable means to potentiate the answer-back means of a callmg station when the users signal transmitted from said station corresponds with that for which the central-station means is manually set,

16. In a system of the character described, the combination of a line; a plurality of sending-station equipments each comprising a plural-digit signal-transmitter adapted to transmit a selectively-set signal individual to the user and a constant station-number signal, and an electrically-operated answerback signal-means; and a central station equipment comprising circuit-controllingmeans manually settable to accord with the plural-digit signal and a signal-responsive circuit-controlling selector having parts respeotlvely movable in response to impulse groups of the signal-digits, of the users signal, said selector coacting with the manually-settable means to potentiate the answer'- back means of a calling station when the mitter is wor the answer-back means of a calling station when the signal transmitted from said station corresponds with that for which the.

central-station means is manually set. v

18. In a system of the character described, the combination of signal circuit connections, lock out circuit connections; a'plurality of sending-station equipments each comprising a plural-impulse signal-transmitter, a transmitter-disabling or lockout means in the look-out circuit arranged to prevent transmitter o eration while any other transking, and an electrically-operated answer-back signal-means associated with the sign-a1 circuit; and a central station equipment comprising means automatically to potentiate the lock-out circuit for all other stations during the operation of the transmitter of any station, circuit controlling means selectively settable to accord with any signal to be answered, and an automatic circuit-controlling selector, responsive to the transmitter-initiated signals, cooperating v with said settable 'means to potentiate the answer-back means of the calling station when the signal transmitted accords with that for which the said settablemeans is set.-

19. In a system of the character described, the combination of signal circuit connections lock out circuit connections; a plurality of sending station equipments, each comprising a transmitter associated with the signal circuit constructed to transmit different users signals, an answer back signal means associated with said signal circuit and electro responsive lock-out means associated with the lock-out circuit and adapted to prevent transmitter operation, each said transmitter adapted to preliminarily close the look-outcircuit at the sending station and thereafter to effect its signal circuit closures; and a central station equipment comprising means for potentiating the look-out circuit connections for all other transmitters upon signalcircuit closure by the sending transmitter, and means responsive to the Siillfl-l transmission instrumental in closing t e circuit for the answer-back means at the sendlng station.

20. In a system of the character described,

means at one station for transmitting different selected signals, answer-back means associated therewith, means at another station for automatic response to any selected signal, means at the last said statlon locally controlled and selectively settable to accord with any chosen signal and coop mtmg with the starting means responsive to a signal responsive means to condition the answer back means for operation only when the signal transmitted accords with that for which said means is selectively set.

21'. In a system of the character described, the combination of a three-wire line, at each sending station signal-circuit switches and an answer back means bridged across two of said wires, lock-out means and a switch therefor associated with the third wire, and transmitter mechanism for working the said switches of the lock out means, signal circuit and answer back in proper sequence; and at a central station means associated with the signal circuit wires for potentiating the lock out wire, settable circuit closing means for correspondence with any signal to be answered, and, in cooperatiton with the last said means, a signal-responsive circuit controlling selector for potentiating a circuit for the answer back means at the calling station when the signal transmitted accords with that for which said central station means is set.

22. In a system of the character described, the combinatiton of a line, a lural digit signal-transmitter, answer-beet means associated with said transmitter, a central station apparatus comprising electro-responsive means movable to different positions in response to different plural-digit si nals, and means operable to correspond with some selected plural-impulse-signal, and means controlled by the transmitter and other means controlled by the position of said electro-re- 1o. sponsive means jointly instrumental in closing a circuit for the answer back means afterthe transmitter has sent its signal.

23. In a system of the character described, the combination of a line; a plural-digit im- 10 pulse-transmitter and a number-indicatingmeans comprisin a step up device responsive to th signa ing impulses, a shifter device controlled by said step up to advance after each signal-digit, and number wheels 11. successivel conditioned, by the shifter, for operation y the step up device each to record its di it of the signal an means for automatically releasing the parts of said number-indicating means after completion 1. of a signal-registration.

24. In a system of the character described,

a line, a plurality of sending-station equipments each having a self-restoring, pluraldigit electrical-impulse transmitter, each 13. said transmitter having means to close the line preliminarily to signal transmission, and central station equipment comprising reliminary impulse to condition the signa-displaying 1: devices for operation, and signal displaying devices comprising a step upv device res on sive to the transmitter-1m ulses, a shifter controlled by said step up evice for operation after each impulse group, nm'nberi3.

wheeis successively conditioned, by said shifter, for operation by the said, step-up means, and automatic means timed 1n operation b said shifter-means for restoring the digit signal of an ascertained num er of digits; and central station equipment com-f prlsing recorder means having a step-up .gde-

vice responsive to the signal impulses, a shifter. controlled by the step-up device for actuation during dwells in the signaling sequence, number-wheels successively conditioned, by the shifter, for operation b the step up means, and means automatica ly to print the record of said wheels.

26. In a system of the character described the combination of a line; a plurality of sending-station equipments each comprlsing a self-restoring transmitter adapted for manual settin to transmit a selected plurel-digit signa of an ascertained number of digits; and central station equipment comprising recorder means having a step-up device responsive to the signal impulses, a shifter controlled by the step-up device for actuation during dwells in the signaling sequence, number-wheels successively conditioned, by the shifter, for operation by the step up means; means timed by the shifter automatically to print the record of said wheels and shifter-timed means thereafter to release the recorder parts.

27. In a system'of the character described,

the combination of a line; a plurality of sending-station equipments each comprising a self-restoring transmitter adapted for manual setting to transmit a selected luralgit signal of an ascertained num er of digits; and central station equipment comprising recorder means havinga step-up device responsive to the signal impulses, a shifter controlled by the step-up device for actuation during dwells in the signaling sequence, number-wheels successively conditioned, by. the shifter, for operation by the step' up means; means timed by theshifter automatically to print the record of said wheel and means controlled by the printing means for releasing the recorder means.

28. In a system of the character described, the combination with a line, of a signal transmitter having a definite cycle of operations, 'signal receiving means cyclically operable in .responseto said transmitter operations, automatic release means for said receiving means, operable in predetermined relation to the signaling cycle, and automatic emergency release means, operable to release the signal-responsive means, and controlled by said signal responsive means for restraint from performin its releasing operation during the norma 'cyclic operation of said signal-responsive means.

.29. In a system of the character descrlbed, the combination of a-line, a transmitter having a definite signaling cycle and adapted to transmit plural-digit number signals in definite time; signal responsive means includ ing a part movable at each dwell in the signa ing cycle, anormal, automatic release means for the signal responsive means, operable to release the latter at a pretetermlned point in the signal-receiving cycle; and emergency release means for said signal-re sponsive means retarded and controlled by the said part that moves during dwells and operable to release upon undue prolongation of time between operations of said part, whereby the signal-responsive means is selfrestoring after a complete or an incomplete signal. y 7

30. In a system of the character described, the combination of a line, aplural-digit signal transmitter, signal responsive means comprisin'c'a step up responsive to signal impulses ind a shifter controlled by said step up and actuated upon. dwells between digit-groups of impulses; recorder parts controlled by the shifter and moved bythe step-up device; normal releasing means for said recorder parts; and emergency releasing means comprising an electro-responsive device operable to efi'ect a release of the recorder parts upon predetermined continuous operation and means controlled by the shifter means for interrupting its continuity of operation, thereby to prevent emergency release as long as the shifter device operates at its normal-signal-responsive times.

31. In a system of the character described, the combination of a line, a signal transmitter comprising means for preliminarily closing the line connections and thereafter transmitting a plural digit number-signal, and a receiving station equipment comprising an electro-responsive starting device responsive to the preliminary impulse, an electro-responsive shifter means and an electro-responsive step up means, both said means connectible with the line by the starting device, said step up device controlling the shifter, for operation of the latter during signal-dwells, meansfor indicatin the signals having number wheels successlvely conditioned, by the shifter means, for operat'ion by the step up means, whereby each group of impulses representing a different digit sets forward a different wheel, and automatic releasing means for said indicating means.

32. In a system of the character described, the combination ofa line, a plural digit signal transmitter, an answerack signal means having its circuit controlled in part by the transmitter, means responsive to the 

